refactor: align templates with old cli definition

[Hweinstock]

Problem

The new CLI has a new definition of templates that is not fully flushed out and diverges from the old CLI. We want to get e2e functionality first, before rethinking this.

Solution

• Templates now again refer to the asset rendering, and the flag for templates refers to flag presets.
• remove byo support to simplify runtime handler for initial version.
• bring parity to create flags to what was discussed in (basically what was in the old cli).
• adjust runtime flags to match the create flags.
• make minimal backend changes to support new interface.

Future Work

Want to refactor the templates to split up template parameters from template identifiers (i.e. what determines the base vs rendered in with handlebars. )

Testing

• added unit tests that exercise the command e2e.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.36%. Comparing base (9c57c40) to head (4a80a21).
⚠️ Report is 1 commits behind head on refactor.

Additional details and impacted files

@@            Coverage Diff            @@
##           refactor    #2094   +/-   ##
=========================================
  Coverage     97.36%   97.36%           
=========================================
  Files           410      410           
  Lines         24796    24819   +23     
=========================================
+ Hits          24142    24165   +23     
  Misses          654      654           

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[Hweinstock]

i plan to refactor this in a future PR. We're going to want some of these parameters to determine the asset templates to render from, and some of them to be rendered into it with handlebars. However, this felt like the smallest change I could make to keep it functional with the new interface.

This PR is intended to focus on aligning the handlers with what we want, then we work backwards from there to implement the functionality we need to support it.